Operation of electrical devices, such as high-power semiconductor devices, high-power lasers, microprocessors and/or light emitting diodes (LEDs), is often associated with generation of heat. The heat is a byproduct that may have an injurious effect on performance and lifetime of the electrical device. Effective cooling is therefore useful and desired in many applications. As an example, a luminaire or lighting device which is capable of providing a high luminuous flux may require efficient cooling of the light sources included in the luminaire or lighting device, if the heat generated by the light sources is to have no or only little detrimental effect on the lifetime of the luminaire or lighting device. High-bay luminaires (that is, luminaires which are utilized in high-ceiling environments such as industrial and warehousing applications) based on LED light sources may generate light having a luminous flux up to about 25 klm or more. The ambient temperature in environments where high-bay luminaires are employed may be up to 50° C. or more, whereas the maximum allowable LED solder temperature is usually between about 80° C. and 100° C., such as, for example, 85° C. or 95° C. In order to cool high-bay luminaires, heat exchange component(s) made of Al may for example be employed. However, such Al heat exchange component(s) are relatively expensive, due to their relatively high weight (Al has a relatively high cost per kg) and because the Al heat exchange component(s) typically are made by dye-casting, which is a relatively expensive process. US 2014/0292192 A1 discloses an LED bulb comprising a structural shell formed by folding a flat printed circuit board (PCB) into a three-dimensional polyhedron shape and a fitting for removably coupling the bulb to a light socket. The PCB comprises a plurality of LEDs, at least one LED mounted electronically on a plurality of faces of the polyhedron, and a driver circuit for driving each LED. The perimeter of the PCB is shaped to join adjacent faces. Each LED produces minimal excess heat, which is partially conducted by a metallic heat sink bridge to the PCB and dissipated to the air through the PCB and through a plurality of spaces in the shell. US 2014/0292192 A1 discloses ventilation holes drilled in the PCB to promote air circulation from inside to outside of the folded LED bulb. According to US 2014/0292192 A1, the holes help to dissipate heat generated by LEDs, and may further increase the lifetime of the LED bulb. However, there is still a need in the art for increased efficiency and/or capacity in dissipation of heat generated in or by electrical devices.